Geologists believe they have found near Ranchi what every gold-digger dreams of: the host rock that gives the Subarnarekha river its sparkling moniker.

Gold nuggets are occasionally found on the bed of the river, helping it live up to the name Subarnarekha (streak of gold) and tantalising some villagers who keep panning for the precious metal.

But it was not known where the host rock — within which the bulk of the gold deposit lies — is located.

Sources in the Geological Survey of India (GSI) have now disclosed that a team has more or less zeroed in on the location after four years of exploration.

The host rock sits somewhere near three hamlets — Lungtu, Parasi and Sindauri — in Ranchi district, the sources said. The area is around 70 km from the heart of Ranchi.

A word of caution for those spinning dreams like the Fortyniners — the fortune-hunters who stampeded to California between 1848 and 1855 and gave the world the phrase “gold rush”.

The Ranchi host rock is surrounded by dense reserve forests known for Naxalite presence. The GSI has also put in place security measures.

Besides, there are no easy pickings of gold nuggets. “It requires lot of work and technology to extract gold ore from the rock,” a Jharkhand mines department official said.

But those living in nearby villages are seen regularly straining water in the Subarnarekha in the hope of striking pay dirt.

The 470-km-long river rises from the Chhotanagpur plateau, passes through Jharkhand and enters Bengal before emptying into the Bay of Bengal in Balasore of Orissa.

If the GSI’s preliminary finding — yet to be made official — is established beyond doubt, it will be a big breakthrough for Jharkhand.

The host rock, said to be 3,500 million years old, is estimated to shelter gold ore reserves of over 2.38 million tonnes. The rock is 100 km long and more than 150 m wide.

“The GSI’s findings are both interesting and beneficial for the state. The GSI will continue exploring for some more time. The state government is awaiting its final report before it takes any decision,” Jharkhand mines and geology secretary Jai Shanker Tiwari said.

“The deposits are scattered within different zones of the host rock. Our work in that area will continue for the next couple of years to determine the specific zones with gold deposits and the exact quantity of ore,” a GSI source said.

For Jharkhand, it will be the second zone with proven deposits of gold reserves after Kunderkocha in East Singhbhum.